Extrusion print head including at least one cooling system

Abstract

Extrusion print head comprising at least one cooling system. The invention relates to an extrusion print head (12) for a 3D printer, comprising a chamber (20) containing a mixture of material to be extruded, having at least two components, a nozzle (18), and at least one temperature control system (26) configured to at least cool the mixture of material present in the chamber (20). Due to this temperature reduction, the mixture remains fluid or pasty in the chamber and can still be extruded via the nozzle (18). The invention also relates to a three-dimensional printing device comprising at least one such print head. Figure 9

Description

Title of the invention: Extrusion print head comprising at least one cooling system

[0001] The present application relates to an extrusion print head of a mixture of at least two components comprising at least one cooling system and to a three-dimensional printing device incorporating at least one such extrusion print head.

[0002] According to one embodiment, a three-dimensional printing device, also called a 3D printer, comprises at least one extrusion print head configured to deposit at least one bead of material and at least one mechanism for moving the extrusion print head. The extrusion print head comprises at least one nozzle through which the bead of material exits, at least one mixing chamber in which at least two components are mixed, at least two feeds, one for each component, configured to supply the chamber with components, and a system for pushing the mixture of the two components from the mixing chamber to the nozzle.

[0003] In addition to the extrusion print head, the 3D printer may include a curing system, such as a UV lamp for example, configured to harden the newly deposited bead of material, said curing system being separate from the print head.

[0004] According to one application, the material deposited by the extrusion print head is a two-component silicone, the first component being a silicone-based material containing non-crosslinked polymers, the second component being a catalyst (or hardener) suitable for causing the crosslinking process of the polymers of the silicone-based material when the first and second components are mixed.

[0005] In operation, when the flow of deposited material decreases or is stopped, such as between two prints, the two-component silicone stagnating in the mixing chamber tends to crosslink, which prevents any further deposition and requires changing the mixing chamber.

[0006] Due to the risks of crosslinking in the mixing chamber, such an extrusion print head does not allow the printing of large parts or certain parts requiring reduced material flow rates at certain times.

[0007] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0008] To this end, the invention relates to an extrusion printing head for a 3D printer which includes a chamber containing a mixture of material to be extruded comprising at least two components, a nozzle and at least one temperature control system configured to at least cool the mixture of material present in the chamber.

[0009] Lowering the temperature of the mixture in the chamber prevents the components from cross-linking. This prevents the mixture from hardening in the chamber and keeps it fluid or pasty, allowing it to be extruded through the nozzle. This makes it possible to stop the extrusion of the mixture or significantly reduce the extruded material flow rate.

[0010] According to another feature, the extrusion print head includes at least one moisture collector configured to collect at least one condensate forming on a surface of the extrusion print head, and at least one evaporation system configured to cause the evaporation of the condensate collected by the moisture collector. According to this solution, the water that condenses on the extrusion print head due to the cooling of the material mixture does not run off onto the part being manufactured.

[0011] According to another feature, the temperature control system includes at least one Peltier effect module which has a cold face oriented towards the chamber and positioned close to the latter.

[0012] According to another feature, the extrusion print head comprises: a. A detachable subassembly comprising a cylindrical tubular wall delimiting the chamber, the nozzle connected to one end of the cylindrical tubular wall, and an inlet head connected to a second end of the cylindrical tubular wall, which includes component power supplies, b. a tubular body which includes a through conduit configured to house at least partially the removable subassembly.

[0013] The invention also relates to a three-dimensional printing device comprising at least one extrusion printing head according to one of the preceding characteristics.

[0014] Other features and advantages will become apparent from the following description of the invention, given by way of example only, with reference to the accompanying drawings, among which:

[0015] [Fig. 1] is a side view of a 3D printer illustrating one embodiment of the invention,

[0016] [Fig.2] is a schematic representation of an extrusion print head illustrating one embodiment of the invention,

[0017] [Fig.3] is a side view of an extrusion print head illustrating a mode of implementation of the invention in the locked state,

[0018] [Fig.4] is a perspective view of part of the extrusion print head visible in [Fig.3],

[0019] [Fig. 5] is a perspective view of an evaporation system illustrating a mode of realization of the invention,

[0020] [Fig.6] is a longitudinal section of an extrusion print head illustrating a embodiment of the invention in the unlocked state,

[0021] [Fig.7] is a longitudinal section of a coupling system illustrating a mode of the realization of the invention,

[0022] [Fig.8] is a perspective view of an extrusion print head illustrating a embodiment, in the locked state on part (A) and in the unlocked state on part (B),

[0023] [Fig.9] is a longitudinal section of an extrusion print head illustrating a another embodiment of the invention,

[0024] [Fig. 10] is a perspective and exploded view of an extrusion print head illustrating an embodiment of the invention,

[0025] [Fig. 11] is a perspective view of part of a 3D printer illustrating one embodiment of the invention.

[0026] According to an embodiment in Figures 1 and 11, a three-dimensional printing device 10, also called a 3D printer, comprises at least one extrusion print head 12 configured to deposit at least one bead of material 14 onto a build surface S, at least one movement mechanism 16 configured to move the extrusion print head 12, and at least one enclosure E in which the build surface S and the extrusion print head 12 are positioned. This 3D printer 10 makes it possible, by moving the extrusion print head 12 along at least one predefined path, to produce, layer by layer, a part P. The build surface S can be a surface independent of the part P to be produced or a layer of the part P already deposited.

[0027] The displacement mechanism 16, the enclosure E and the link between the extrusion print head 12 and the displacement mechanism 16 are not further described as they may be identical to those of the prior art.

[0028] According to one application, the deposited material is a two-component silicone, the first component being a silicone-based material containing non-crosslinked polymers, the second component being a catalyst (or hardener) suitable for causing the crosslinking process of the polymers of the silicone-based material when the first and second components are mixed.

[0029] Of course, the invention is not limited to this application and this material. Regardless of the embodiment, the extrusion print head 12 is configured to extrude a mixture of at least two components.

[0030] The extrusion print head 12 includes at least one nozzle 18 through which the material mixture exits in the form of a material bead 14, at least one chamber 20 containing a material mixture to be extruded and a push system 22 configured to push the material mixture to be extruded from the chamber 20 towards the nozzle 18.

[0031] According to an embodiment visible in figures 9 and 11, the thrusting system 22 can be located outside the extrusion print head 12. By way of example, the thrusting system 22 includes at least one pump configured to exert pressure on the material mixture present in the chamber 20 and force it out through the nozzle 18.

[0032] According to another embodiment, the 3D printer includes at least one thrust system 22 located in the chamber 20 (inside the extrusion print head 12) and at least one thrust system located outside the extrusion print head 12 (not part of the extrusion print head 12).

[0033] According to one embodiment, chamber 20 is a mixing chamber in which at least two components are mixed, resulting in the material mixture to be extruded. In addition, the extrusion print head 12 includes at least one component feed 24, one for each component to be mixed in chamber 20.

[0034] According to this configuration, the chamber 20 comprises a cylindrical tubular wall 20.1 which has an inner surface F20 in contact with the mixture of material to be extruded, an outer surface F20' (opposite to the inner surface F20) and an axis of revolution A20. In addition, the nozzle 18 is in the form of a frustoconical tube whose wider end is connected to the tubular wall 20.1 of the chamber 20.

[0035] According to an embodiment shown in Figures 6 and 9, the chamber 20 comprises an element, hereinafter referred to as a mixer 25, configured to mix the components. In this case, the chamber 20 forms a static mixer.

[0036] Of course, the invention is not limited to this embodiment for the extrusion print head 12.

[0037] According to the invention, the extrusion printing head 12 includes a temperature control system 26 for the material mixture present in the chamber 20 configured to at least cool it.

[0038] Lowering the temperature of the material mixture contained in chamber 20 prevents the cross-linking of the mixture's components. Thus, the mixture does not harden in chamber 20 and remains fluid or pasty, allowing it to continue being pushed through nozzle 18. It is also possible to stop printing or significantly reduce the flow rate of the printed material mixture at certain times.

[0039] The temperature control system 26 is configured to cool the material mixture in the chamber 20 to a temperature less than or equal to a threshold temperature that depends on the components being mixed. For example, the material mixture to be extruded is maintained at a temperature less than or equal to 10°C, preferably between 0 and -15°C, for a two-component silicone-based mixture.

[0040] According to one configuration, the temperature control system 26 is configured to both cool and heat the material mixture in the chamber 20. In this configuration, the temperature control system 26 can, at a given moment, heat the material mixture in the chamber 20 to make it more fluid or promote cross-linking, and at a given moment, cool the material mixture in the chamber 20 to prevent it from hardening, particularly when printing is stopped or slowed down.

[0041] According to one embodiment, to promote heat transfer between the inside and outside of chamber 20, the wall 20.1 of chamber 20 is made of a thermally conductive material.

[0042] The extrusion printing head 12 includes a body 28 surrounding the chamber 20 and incorporating at least one temperature control system 26.

[0043] According to one arrangement, the body 28 and the wall 20.1 of the chamber 20 form a single and same piece.

[0044] According to another arrangement, the body 28 and the wall 20.1 of the chamber 20 are two separate elements. According to this arrangement, the chamber 20 is removable and can be separated from the body 28 to be replaced by another chamber, for example.

[0045] According to one embodiment, the extrusion printing head 12 includes a removable subassembly 30 (such as a static mixer for example) which includes a cylindrical tubular wall 20.1, delimiting the chamber 20, which extends between first and second ends and a mixer 25 positioned in the chamber 20, a nozzle 18 connected to the first end of the cylindrical tubular wall 20.1 and an intake head 32, connected to the second end of the cylindrical tubular wall 20.1, which includes component feeds 24.

[0046] To receive the removable subassembly 30, the body 28 is tubular and includes a through conduit 28.1 configured to house at least partially the removable subassembly 30.

[0047] According to one configuration, the extrusion print head 12 includes a coupling system 34, 34' for connecting the removable subassembly 30 and the body 28.

[0048] According to an embodiment visible in [Fig.9], the coupling system 34 comprises a threaded section 34.1 at the level of the through conduit 28.1 and a threaded section 34.2 positioned at the level of the inlet head 32 and configured to screw into the threaded section 34.1. According to this embodiment, the extrusion printing head 12 must be disassembled in order to extract the removable subassembly 30.

[0049] According to another embodiment visible in Figures 3, 6 to 8, the coupling system 34' is configured to occupy a locked state, visible in Figures 3, 6 and part (A) of [Fig.8], in which it immobilizes the removable subassembly 30 in the through channel 28.1 of the body 28 and an unlocked state, visible in [Fig.7] and part (B) of [Fig.8], in which it allows the removable subassembly 30 to slide in the channel 28.1 of the body 28 and to be extracted from the print head by extrusion 12.

[0050] According to one configuration, the coupling system 34' comprises at least one latch 34.1' configured to move radially (perpendicular to the axis of the through conduit 28.1) between an extended position, corresponding to the locked state, and a retracted position, corresponding to the unlocked state, at least one housing 34.2' located in the removable subassembly 30 and configured to house at least one latch 34.1' in the extended position, and a control 34.3' configured to control the extended or retracted position of the latch 34.1'. By way of example, the removable subassembly 30 comprises a peripheral groove that provides the housing function 34.2' for all the latches 34.1'. The control 34.3' may be a movable ring along the body 28 between a first position, visible in Figures 3, 6 and part (A) of [Fig.8], in which the ring holds all the latches in the extended position (in which they are housed in their housing(s) 34.2') and prevents them from moving into the retracted position, as well as a second position, visible in [Fig. 7] and part (B) of [Fig. 8], in which it allows each latch 34.1' to move from the extended position to the retracted position (in which they are located out of their housing(s) 34.2'). Each latch 34.1' is at least partially housed in a radial orifice 34.4' through the body 28.

[0051] According to a first arrangement visible in [Fig.7], each lock 34.1' comprises two balls and at least one spring interposed between the two balls.

[0052] According to a second arrangement visible in [Fig.3], each lock 34.1' comprises a hollow pin 34.5' configured to cooperate with a housing 34.2' provided at the level of the removable subassembly 30, a ball 34.6' configured to cooperate with the control ring 34.3' and a spring 34.7' positioned between the hollow pin 34.5' and the ball 34.6'.

[0053] Of course, the invention is not limited to these embodiments for the coupling system 34, 34'. Other solutions are conceivable for temporarily connecting the removable sub-assembly 30 and the body 28.

[0054] To promote heat exchange between the body 28 and the mixture of material present in the chamber 20, the body 28 is in intimate contact with the wall 20.1 of the chamber 20 and / or a thermally conductive filling material is provided to fill the space between the body 28 and the wall 20.1 of the chamber 20.

[0055] According to an embodiment visible in [Fig.2], the temperature control system 26 comprises at least one section of at least one heat transfer fluid circuit 36 ​​positioned near the chamber 20. This heat transfer fluid circuit 36 ​​comprises a means for regulating the temperature of the heat transfer fluid 36.1, located away from the extrusion print head 12, configured to regulate the temperature of the heat transfer fluid circulating in the heat transfer fluid circuit 36.

[0056] When the temperature control system 26 is configured to only cool the mixture of matter present in the chamber 20, the temperature control means for the heat transfer fluid 36.1 is adapted to cool the heat transfer fluid circulating in the heat transfer fluid circuit 36.1. As an example, a thermodynamic machine is used to cool the heat transfer fluid.

[0057] When the temperature control system 26 is configured to alternately cool and heat the material present in the chamber 20, the temperature control means for the heat transfer fluid 36.1 is of the reversible type and adapted to alternately cool or heat the heat transfer fluid circulating in the heat transfer fluid circuit 36.1. By way of example, a reversible thermodynamic machine is used to cool or heat the heat transfer fluid.

[0058] According to an embodiment shown in [Fig. 9], the extrusion print head 12 (more particularly its body 28) comprises at least one Peltier effect module 38 having a cold face F38 oriented towards the chamber 20 and positioned near it, a hot face F38' opposite the cold face F38, and at least one connector 38.1 configured to be connected to an electrical power supply Alim. According to this embodiment, the Peltier effect module 38 is configured to generate cold at the cold face F38, when it is electrically powered, and to cool the material mixture present in the chamber 20.

[0059] According to one arrangement, the body 28 comprises a tubular Peltier effect module 38 having an inner face corresponding to the cold face F38 and an outer face corresponding to the hot face F38', as well as an inner tubular portion 40.1 having an outer face in contact with the cold face F38 of the Peltier effect module 38 and an inner face oriented towards the chamber 20, in contact with its wall 20.1. In addition, the body 28 comprises an outer tubular portion 40.2 having an inner face in contact with the hot face F38' of the Peltier effect module 38. According to one arrangement, the extrusion print head 12 comprises a body 28 surrounding the chamber 20 and several Peltier effect modules 38 positioned around the body 28.

[0060] According to another arrangement visible in [Fig. 10], the body 28 has a polygonal cross-section (equilateral triangle) and several faces. In addition, each Peltier effect module 38 is in the form of a plate pressed against one of the faces of the body 28.

[0061] According to one embodiment, the extrusion print head 12 includes at least one heat dissipation system configured to dissipate the heat generated by the Peltier effect module(s) 38, such as at least one heat transfer fluid circuit or at least one radiator 41 (visible in [Fig. 10]).

[0062] Of course, the invention is not limited to these embodiments for the temperature control system 26 capable of cooling the material mixture present in the chamber 20. In addition, the extrusion printing head 12 could combine several temperature control systems 20.

[0063] Regardless of the embodiment, during printing, the enclosure E contains an atmosphere in contact with the outer surface F12 of the extrusion print head 12.

[0064] When the temperature control system 26 cools the material mixture in the chamber 20, the atmosphere contained in the enclosure E has a temperature significantly higher than that of the extrusion print head 12.

[0065] To prevent moisture from appearing on the outer surface F12 of the extrusion print head 12 due to condensation and to prevent water droplets from dripping onto the part being printed, one solution is to regulate the atmosphere inside the enclosure E by drying it. In one embodiment, the 3D printer includes at least one dehumidifier configured to dry the atmosphere inside the enclosure E. This solution is not satisfactory because the volume of air to be treated is significant. Furthermore, the air dehumidification operation must be performed each time the enclosure E is opened, particularly when removing the printed part or changing the material reservoir. However, this dehumidification operation is relatively long and energy-intensive.

[0066] According to another embodiment visible in [Fig.2], the outer surface F12 of the extrusion print head 12 is thermally insulated to prevent the propagation of cold from the temperature control system 26 to the outer surface F12 of the extrusion print head 12. For this purpose, the extrusion print head 12 includes a thermally insulating coating 42 at its outer surface F12.

[0067] According to another embodiment shown in [Fig. 9], the outer surface F12 of the extrusion print head 12 is heated to limit the risk of condensation. To this end, when the extrusion print head 12 includes a Peltier effect module 38, the hot face F38' is oriented towards the outer surface F12 of the extrusion print head 12 and positioned close to it to heat it.

[0068] Alternatively, electrical resistors could be positioned near the outer surface F12 of the extrusion print head 12 to cause heating by Joule effect.

[0069] Of course, the invention is not limited to the systems previously mentioned for limiting the risks of condensation.

[0070] According to an embodiment shown in Figures 2 to 6, the extrusion print head 12 comprises at least one moisture collector 44 and at least one evaporation system 46 configured to evaporate the condensate collected by the moisture collector 44. The moisture collector 44 is configured to collect at least one condensate forming on a surface of the extrusion print head 12 (in particular its outer surface F12). In one arrangement, it is positioned between the extrusion print head 12 and the part to be produced.

[0071] According to a configuration visible in particular in [Fig. 5], the moisture collector 44 and the evaporation system 46 form a single ring-shaped element 48, positioned under the body 28, which has an upper face F48 oriented towards the body 28 of the extrusion print head 12 and has a passage hole 50 allowing the nozzle 18 to pass through. The upper face F48 is delimited by inner and outer edges 48.1, 48.2 sufficiently spaced so that the drops dripping from the body 28 fall onto the upper face F48. The ring 48 may include at least one hollow 52 on its upper face F48 to collect a larger volume of water.

[0072] According to one arrangement, the ring 48 is made of a material that is highly thermally conductive, such as a copper alloy for example.

[0073] According to one embodiment, the extrusion print head 12 includes spacers 54 connecting the ring 48 and the body 28. In one configuration, these spacers 54 are made of a thermally conductive material, such as a copper alloy, to achieve conductive heat transfer between the ring 48 and the body 28. This heat transfer increases the temperature of the outer surface F12 of the extrusion print head in order to limit the risk of condensation or to cause evaporation of at least some of the water condensed on the outer surface F12 of the extrusion print head 12.

[0074] According to one configuration, the ring 48 is heated to a high temperature to evaporate the water. For this purpose, the ring 48 includes at least one electrical resistance for heating it.

[0075] Of course, the invention is not limited to this embodiment for causing heating of the ring 48. In addition, the invention can combine at least one evaporation system configured to cause the evaporation of the already condensed water and at least one heating system for the outer surface F12 of the extrusion print head 12 or for limiting its cooling.

[0076] According to a preferred embodiment, the extrusion printing head 12 includes at least one Peltier effect module 38 for cooling the material mixture and at least one heat transfer fluid circuit for dissipating the heat generated by the Peltier effect module(s) 38. Optionally, a heating system is provided to warm the nozzle 18 in order to limit the appearance of condensation at the nozzle 18.

[0077] The extrusion print head 12 includes a removable subassembly 30, namely a static mixer, mounted in the extrusion print head 12 as illustrated in [Fig. 9]. Thus, the static mixer is inserted into the extrusion print head 12 when it is removed from its end opposite the nozzle 18.

Claims

Demands

1. Extrusion print head for a three-dimensional printing device, said extrusion print head being configured to extrude a mixture of material comprising at least two components and having a chamber (20) which contains the mixture of material to be extruded and a nozzle (18), characterized in that the extrusion print head includes at least one temperature control system (26) configured to at least cool the mixture of material present in the chamber (20).

2. Extrusion print head according to claim 1, characterized in that the temperature control system (26) is parameterized to cool the material mixture present in the chamber (20) to a temperature less than or equal to 10°C, preferably between 0 and -15°C.

3. Extrusion print head according to any one of the preceding claims, characterized in that the temperature control system comprises at least one Peltier effect module (38) which has a cold face (F38) oriented towards the chamber (20) and positioned close to the latter, a hot face (F38') opposite the cold face (F38) and at least one connector (38.1) configured to be connected to an electrical power supply.

4. Extrusion print head according to the preceding claim, characterized in that it comprises a body (28) surrounding the chamber (20) and several Peltier effect modules (38) positioned around the body (28), each Peltier effect module (38) having an inner face corresponding to the cold face (F38) in contact with the body (28).

5. Extrusion print head according to the preceding claim, characterized in that the body (28) has a polygonal cross-section and several faces and in that each Peltier effect module (38) is in the form of a plate pressed against one of the faces of the body (28).

6. Extrusion print head according to any one of claims 3 to 5, characterized in that the extrusion print head (12) comprises at least one heat dissipation system configured for dissipate the heat generated by the Peltier effect module(s) (38).

7. Extrusion print head according to any one of the preceding claims, characterized in that it comprises at least one moisture collector (44) configured to collect at least one condensate forming on a surface of the extrusion print head (12) and at least one evaporation system (46) configured to cause the evaporation of the condensate collected by the moisture collector (44).

8. Extrusion print head according to the preceding claim, characterized in that it comprises a tubular body (28) surrounding the chamber (20) and in that the moisture collector (44) and the evaporation system (46) form a ring (48), positioned under the body (28), which has a top face (F48) oriented towards the body (28) as well as a through hole (50) for the nozzle (18).

9. Extrusion print head according to the preceding claim, characterized in that the ring (48) comprises at least one hollow (52) at its upper face (F48).

10. Extrusion print head according to any one of claims 8 to 9, characterized in that the extrusion print head (12) comprises spacers (54) made of a thermally conductive material connecting the ring (48) and the body (28).

11. Extrusion print head according to any one of the preceding claims, characterized in that the temperature control system (26) comprises at least one section of at least one heat transfer fluid circuit (36) positioned near the chamber (20).

12. Extrusion print head according to any one of the preceding claims, characterized in that the chamber (20) is delimited by a cylindrical tubular wall (20.1) and in that the extrusion print head comprises a body (28) surrounding the chamber (20), the body (28) and the wall (20.1) being two separate elements to make the chamber (20) removable.

13. Three-dimensional printing device comprising at least one extrusion print head according to one of the preceding claims.

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